1. Technical Field
The invention relates generally to an electronic device, and more particularly, to the electronic device and a transmitter DC offset calibration method performed by the electronic device.
2. Related Art
To communicate with another electronic device, an electronic device such as a mobile phone, a tablet computer, a laptop computer, or a media player, can include a digital baseband circuitry, a digital-to-analog converter (DAC), and a transmitter front-end (TX FE). To put it simply, the digital baseband circuitry first generates a digital signal upon which transmission is based. Then, the DAC converts the digital signal into a baseband signal. Next, the TX FE up-converts the baseband signal to generate an RF signal, amplifies the RF signal, and passes the amplified RF signal to an antenna for transmission. For example, the TX FE may include the following components: a local oscillator (LO) for generating a carrier signal; a mixer for generating the RF signal by mixing the baseband signal with the carrier signal; and a programmable gain amplifier (PGA) for amplifying the RF signal.
An analog signal on the aforementioned transmission path may have some direct current (DC) offset. A small DC offset may be negligible; but if the DC offset is large, it may affect the communication quality. To prevent the communication quality from degrading, the DC offset must be calibrated properly.